Lab talk

Jan 2, 2008

Possible role for nanotechnology in the treatment of cataracts

If we live long enough we will all develop cataracts – a clouding of the crystalline lens of the eye. Wei Chen, a nanotechnologist, approached a lens physiologist (Professor Barbara K Pierscionek of the University of Ulster) and an ophthalmologist (Ronald A Schachar, MD, PhD of the University of Texas at Arlington) to study the biochemical causes of cataractogenesis.

The crystalline lens is a transparent biconvex totally epithelial structure that is enclosed within a thin capsule. The approximate equatorial diameter and central thickness of the human lens is 9 mm and 4 mm, respectively. The lens is comprised of tightly packed epithelial cells – lens fibers – enclosed in a thin capsule. Although the lens fibers have few organelles their protein contact is very high. The lens consists of 35% protein and 65% water. Lens transparency depends on short-range order of the proteins within the lens. Changes in lens protein structure cause the scattering that reduces lens transparency, which results in a cataract. To begin to understand the mechanism of caractogenesis the authors are using nanotechnology.

The author’s preliminary studies demonstrated that fluorescent nanoparticles or quantum dots of a few nanometers in size will passively diffuse into lens fibers but will not pass through the lens capsule. The authors are now using lens cultures with nanoparticles attached to biocompatible tags to study the controlling factors responsible for the differences in diffusion and to identify the early structural changes that precede opacification and cataract formation. These studies may lead to a medical treatment for cataracts – a major cause of blindness – as nanoparticles have the potential to act as carriers of chemotherapeutic agents.

About the author

Wei Chen, PhD, is an assistant professor of nanobio physics at the Department of Physics at the University of Texas at Arlington. He has been developing unique design fluorescent nanoparticles that are having wide applications. He has developed methods for using scintillation nanoparticles to combine photodynamic therapy and radiotherapy for deep cancer treatment, near-infrared nanoparticles for cancer imaging and fingerprint detection on soft substrates as well as for radiation detection for homeland security.
Barbara K Pierscionek, PhD, is professor of vision science at the University of Ulster. She is involved in studying the biochemistry and the optics of the eye lens to determine how the structure may affect function and the changes that may occur with cataract formation.
Ronald A Schachar, MD, PhD is adjunct professor of physics at the University of Texas at Arlington. He is involved in studying aging of the lens and its clinical implications in the etiology of presbyopia and glaucoma.